Background: Health care is inevitably associated with an increased risk of patient safety. Due to the complexity of attitude of care, the safety culture and the care of patients play a major role in safe care. Objectives: The present study aimed to assess the quality of safe nursing care in the Cardiac Care Unit. Methods: This is a descriptive study conducted in the Cardiac Care Unit of Baqiyatallah Hospital in 2018. All nursing staff working in the cardiac care unit comprised the sample of the study. Safe nursing care was measured using a tool designed by Rashvand et al. in 2015. Data were analyzed by SPSS version 21. This study was approved by the ethics committee in BMSU.